RayCJ, phosphorus levels only matter if the engine is an oil user. Then it gets out and goes to the cats. Otherwise, if the engine uses very little oil, its all good to have higher P. I'd guess that would be if it uses less than 1 quart in 5,000 miles.
Originally Posted by Phishin
^^^^^ Yeah. It will mix nicely with Mobil 1 Advanced Fuel Economy 0w20. A long time ago, when I first joined BITOG, there was a guy here who ran a 50/50 mix of Mobil 1R 0w50 and Mobil 1 Advanced Fuel Economy 0w20 in his cars. Yeah, they were high performance cars, and this is just going into a 4 cylinder Accord, but why not? You only live once.....
One thing I realized, and please tell me if I'm wrong: They still run the seal compatibility tests on Racing oil, right? We have depended on the seal compatibilty lists in SN, dexos1, 229.5, etc., yet Racing oil like this Mobil 1 0w50 has no specs. Mobil 1 just says "use it for racing" without reported tests we can hang our hat on. I guess that's good enough. I mean, Mobil has to know this oil could go into almost any brand of race car and engine type (hot Rally hatchbacks, NASCAR, German engines, etc., you know).
Mobil 1 Racing oil (both 0w30 and 0w50) are nearly all-PAO oils when you look at the MSDS sheets for them. Sounds great.
....If you do want a Racing full-PAO 0w-50 oil that is also API SN officially certified (tested), Eneos Racing Street 0w-50 is the one. Amazon has it.
Their Eneos Racing Street 0w-20 is not all-PAO. It's all-Group3+ (like PurePlus) so it should be good. API SN there too. I use that full-strength in my hybrid since it has SN.
Also, mixing.... hmmm.... I assume there wouldn't be additive clash. I wouldn't use more than 20% of the sump as Mobil 1 Racing oil.
My suggestion would be to first do an oil change with 0w20 for the winter, then leave room in your sump for 1/2 quart of make-up oil half-way through your oil change interval to allow the Mobil 1 Racing oil additives to replace the depleted Mobil 1 Advanced Fuel Economy 0w20 (or whatever anybody uses as the base) addtives, and thicken the oil a tad for summer. .... Because it does appear, from the VOA, that Mobil 1 Racing oil has detergents like street oil, & certainly gobs of ZDDP & moly we like.